1. Field of the Invention
The present invention relates to the field of telecommunications. More particularly, the present invention relates optimizing the deigns of trunk networks in the public switched telephone network by routing based on analysis of congested switches.
2. Acronyms
The written description provided herein contains acronyms which refer to various telecommunications services, components and techniques, as well as features relating to the present invention. Although some of these acronyms are known, use of these acronyms is not strictly standardized in the art. For purposes of the written description herein, the acronyms are defined as follows:                Advanced Intelligent Network (AIN)        Central Exchange Service (Centrex)        Central Office (CO)        Dual Tone Multi-Frequency (DTMF)        Graphical User Interface (GUI)        HyperText Mark-Up Language (HTML)        HyperText Transfer Language Protocol (HTTP)        Interactive Voice Response (IVR)        Line Information Database (LIDB)        Numbering Plan Area (NPA)        Outgoing Call Control (OCC)        Personal Computer (PC)        Personal Call Manager/Personal Communications Manager (PCM)        Personal Identification Number (PIN)        Private Branch Exchange (PBX)        Public Switched Telephone Network (PSTN)        Service Control Point (SCP)        Service Management System (SMS)        Service Switching Point (SSP)        Signaling System 7 (SS7)        Signaling Transfer Point (STP)        Terminating Attempt Trigger (TAT)        Transaction Capabilities Application Part (TCAP)        Transmission Control Protocol/Internet Protocol (TCP/IP)        World Wide Web (WWW)        
3. Background Information
Telephones have become a practical necessity in today's society, from both personal and professional perspectives. Telephone calls exchanged in the course of daily activities assist in enabling the convenience and efficiency of modern living. However, telephone calls likewise may become disruptive to families and businesses alike, when they are excessive, poorly timed or inappropriate. Often, the disruptive telephone calls are being made to or initiated by a relatively small group.
Consequently, various telephone services have been developed to enable customers to prevent selected incoming and outgoing telephone calls from connecting through the public switched telephone network (PSTN). Incoming calls may be blocked based on selected time periods or on the calling telephone number. For example, if a family wishes not to be disturbed at dinner time, the subscriber initiates an incoming call blocking service, e.g, depressing a predetermined sequence of keys of a dual tone multi-frequency (DTMF) telephone, to avoid receiving all incoming calls from 5:30 p.m. to 7:00 p.m. Similarly, a business that conducts a daily staff meeting from 8:00 a.m. to 9:00 a.m. redirects all incoming calls to an answering service. Likewise, conventional services enable subscribers to block calls from selected telephone numbers, e.g., telemarketers, to avoid harassment or interruptions.
Outgoing calls may similarly be blocked based on selected time periods or on called telephone numbers. Conventionally, outgoing calls are blocked during certain hours selected by the subscriber. For example, calls from a teenager's telephone can be blocked from 9:00 p.m. to 7:00 a.m. the following day in order to prevent excessive nightly use of the telephone and to encourage the teenager to do homework or go to bed. Further, a typical application of controlling outgoing calls based on telephone numbers is blocking calls to “900” numbers from the subscriber's business or home, avoiding potentially inappropriate communications and undesirable bills. Also, conventional services typically enable blocking of all long distance calls initiated from the subscriber's telephone.
Current telecommunications services include several drawbacks. One is that call blocking may negatively affect the subscriber by preventing completion of important calls to and from the subscriber's telephone number. For example, a service that merely blocks all incoming calls to the subscriber's home during a preselected time period each day, or originating from a particular area code, may inadvertently prevent the subscriber from calling his own home. Similarly, the subscriber is unable to complete a telephone call from his own home during a restricted period, or to a restricted number, without first deactivating the call blocking feature. The unblocking process is time consuming and, in an emergency situation, potentially disastrous.
Another disadvantage is that the subscriber does not know what and when telephone calls are blocked, unless the subscriber also subscribes to (and activates) a separate service, e.g, caller identification, automated voice messaging, etc., that captures the information. Further, conventional call blocking systems do not provide instantaneous (or nearly instantaneous) call blocking data from the PSTN to the customer.
In addition, there is no convenient way to interactively access call blocking services, e.g., accessing records of blocked calls, activating schedules, activating restricted number lists, and the like, that is consistently and reliably available to the customer, regardless of the customer's circumstances and location. For example, conventional call blocking services are generally accessible to the customer either using a DTMF telephone through an interactive voice response (IVR) system in the PSTN or using a graphical user interface (GUI) over the Internet. The IVR communication is often more convenient due to the common accessibility of DTMF telephones. For example, to initiate call blocking, the customer simply goes off-hook at a DTMF subject telephone, dials the service provider number and follows the voice generated instructions to activate the call blocking. However, IVR interaction is time consuming and often tedious and undesirable from the subscriber's point of view. The Internet communication is therefore preferable under many circumstances, because service related data is provided quickly and in easily comprehensible visual (as opposed to audio) formats. However, Internet communications require an Internet accessible device, such as a personal computer or a personal digital assistant (PDA). Internet accessible devices are significantly more expensive than DTMF telephones and less readily accessible.
The present invention overcomes the problems associated with the prior art, as described below.